I wear contacts and alway have a slimy substance on them?

I feel like I'm constantly rubbing my eyes, or cleaning my contacts to try and get some slimy stuff off of them. I just took my contacts out a minute ago and I still felt like there was something slimy in my eye so I looked in the mirror and there was some slime my top inner eyelid. I'm not sure why this always happens to me or what I can do about it. Does anyone else experience this?